Also, I know people in the situation you describe, and its a grind like every other bonus incentivized gig on wall street. People may tell you otherwise, but they're probably sugarcoating. I know a few people who burned out early and started their own companies, and a couple who are continuing the slog for huge bonus payouts. The no free lunch theorem holds true.
For me, I'll finish up this degree and see where things are headed. I'm definitely not set on SV or WS yet, but it'll probably be one or the other.
The lifestyle appeals to some, but not all, and Wall Street's "very high prestige" doesn't really exist outside NYC and its immediate neighbors. For most people, finance is associated with greed-fueled, drug-addled sociopaths who have to pay for sex and companionship, since that's what's portrayed in "Wall Street," "Wolf of Wall Street," the news, etc., and they don't associate that with prestige.
There are a lot of cautionary tales about Wall Street for a reason. Some in finance get out alive, others end up washed up or burnt out, barely maintaining employment, battling chronic depression due to years of abusing their brain chemistry. A million dollar bonus would be nice, but the other stuff I can do without.
Most of them view it as a mercenary job, nothing more. They don't give a shit about finance itself, but they enjoy the money, they enjoy solving problems - especially ones that are seen as impossible - and obviously they also enjoy the deep technical aspects of the job as well. It scratches a lot of different itches and it's a very high prestige gig ("Wall Street", "Wolf of Wall Street", etc.) to boot.
Look at it another way: if they're out in the Valley, they're one of thousands of talented engineers, competing against gender disparity in a very competitive social arena. In NYC, they're young, brash hotshots working less hours for more money with all of the ego, bonuses, and cocaine that goes with it, in an infinitely more exciting city. Tell me which setup you'd rather have.